U.K. Economy on a Wing and a Prayer

A rare breed of emotion has been detected in the U.K. recently: hope for an economic recovery. Adding to a string of recent better-than-expected data releases, Wednesday's labor-market report showed an 8,000 fall in the number of people claiming unemployment benefits in May, a record 29.8 million people in jobs and a growing number of openings. The run of good news is undoubtedly welcome. But the situation remains fragile.

The labor data added to the optimism generated by the recent Markit purchasing managers' indexes for May,...